Delineating complex spatiotemporal distribution of earthquake aftershocks: An improved Source-Scanning Algorithm

Yen Che Liao, Honn Kao, Andreas Rosenberger, Shu Kun Hsu, Bor Shouh Huang

Research output: Contribution to journalArticlepeer-review

34 Scopus citations

Abstract

Conventional earthquake location methods depend critically on the correct identification of seismic phases and their arrival times from seismograms. Accurate phase picking is particularly difficult for aftershocks that occur closely in time and space, mostly because of the ambiguity of correlating the same phase at different stations. In this study, we introduce an improved Source-Scanning Algorithm (ISSA) for the purpose of delineating the complex distribution of aftershocks without time-consuming and labour-intensive phase-picking procedures. The improvements include the application of a ground motion analyser to separate P and S waves, the automatic adjustment of time windows for 'brightness' calculation based on the scanning resolution and a modified brightness function to combine constraints from multiple phases. Synthetic experiments simulating a challenging scenario are conducted to demonstrate the robustness of the ISSA. The method is applied to a field data set selected from the ocean-bottom-seismograph records of an offshore aftershock sequence southwest of Taiwan. Although visual inspection of the seismograms is ambiguous, our ISSA analysis clearly delineates two events that can best explain the observed waveform pattern.

Original languageEnglish
Pages (from-to)1753-1770
Number of pages18
JournalGeophysical Journal International
Volume189
Issue number3
DOIs
StatePublished - Jun 2012

Keywords

  • Asia
  • Computational seismology
  • Earthquake source observations

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